Plant density affects how much food different parts of wheat plants make. Some stems make less food than others, especially in wheat with big spikes. The more plants there are, the bigger the difference in food-making ability between stems. This is because some stems are better at making food than others. The differences in food-making ability also affect how well the plants can use sunlight. Overall, plant density can change how much food different parts of wheat plants make, especially in wheat with big spikes.